The Washington Post ran a rather interesting report this week about the rise of direct-to-consumer DNA tests. I have vague recollections of other recent pieces (which I don’t have time to dig out) about the proliferation of personal DNA testing, so this has been on my mind a bit.
As someone who has spent months of time trying to sequence a few hundred bases of DNA, I think that the advancement of sequencing technology is very exciting. While the human genome has been completed for five years, scientists and clinicians still spend a great deal of difficult time searching for the specific genetic abnormalities which cause disease. Sequencing a whole genome for a few thousand dollars will certainly have a positive impact on the treatment of disease.
On the consumer side, the article mentions a $995 test which proclaims it will “help” clients find mates who “smell sexier, have more orgasms and produce healthier children.” This is all somewhat unserious, and anybody who has a thousand dollars burning a hole in their pocket should be able to spend it how they wish.
The troublesome part of this trend is companies who proclaim to deliver actual health information – susceptibility to chronic disease and cancer, etc. Like Francis Collins, I find this problematic.
The major issue here is that direct-to-consumer test information is completely out of the reach of the clinician. To be clear, increasing direct pricing for health services and tests is a welcome phenomenon. The problem here is that when the clinician is completely uninvolved, not only is the quality of the test a complete wild card, but the relevance of its results is not critically evaluated in the least.
The reality is that genetic tests are of limited value in predicting clinical outcomes. As the article mentions, a positive “hit” for a genetic marker may only increase susceptibility by 10-30%. Environmental and lifestyle factors play a huge role in the progression of any chronic disease. This type of risk balance is complex and difficult for doctors to explain to patients, but it is certainly not going to be explained in the privacy of your own home, or on WebMD. Patients need to review any serious health test information with a trained clinician, plain and simple.
As an anecdote, this article from October provides a disturbing example of the difficulty involved in risk analysis for non-scientist patients. Apparently, among breast cancer patients, the rate of elective mastectomies on the healthy breast doubled between 1998 and 2003. If this is largely for cosmetic reasons, fine. But according to the report, it seems that oftentimes it is done out of some sense of preventative care, which is a travesty. A basic understanding of cancer progression would inform these patients that vigilant screening is the best way to prevent recurrence – by the time a tumor is detected cancer cells have travelled throughout the body. Cutting off healthy parts of your body is not an effective way to prevent disease.
This is exactly the type of fatalistic reasoning that we should strive to avoid. This issue cuts to the overarching disconnect between scientific research and the public understanding, which is a topic for another day. The Krummey Truth is that the scientific basis of direct-to-consumer genetic tests is dubious and currently unregulated (like the carbon offset industry!). Some form of discretion needs to be established to ensure that consumers draw accurate conclusions from their genes.
Tags: DNA testing, Science
